1/*	$NetBSD$	*/
2
3/*
4 * Copyright (C) 2002-2004 Sistina Software, Inc. All rights reserved.
5 * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
6 *
7 * This file is part of LVM2.
8 *
9 * This copyrighted material is made available to anyone wishing to use,
10 * modify, copy, or redistribute it subject to the terms and conditions
11 * of the GNU Lesser General Public License v.2.1.
12 *
13 * You should have received a copy of the GNU Lesser General Public License
14 * along with this program; if not, write to the Free Software Foundation,
15 * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
16 */
17
18#include "lib.h"
19#include "metadata.h"
20#include "toolcontext.h"
21#include "lv_alloc.h"
22
23int lv_is_origin(const struct logical_volume *lv)
24{
25	return lv->origin_count ? 1 : 0;
26}
27
28int lv_is_cow(const struct logical_volume *lv)
29{
30	return lv->snapshot ? 1 : 0;
31}
32
33int lv_is_visible(const struct logical_volume *lv)
34{
35	if (lv->status & SNAPSHOT)
36		return 0;
37
38	if (lv_is_cow(lv)) {
39		if (lv_is_virtual_origin(origin_from_cow(lv)))
40			return 1;
41
42		return lv_is_visible(origin_from_cow(lv));
43	}
44
45	return lv->status & VISIBLE_LV ? 1 : 0;
46}
47
48int lv_is_virtual_origin(const struct logical_volume *lv)
49{
50	return (lv->status & VIRTUAL_ORIGIN) ? 1 : 0;
51}
52
53
54/* Given a cow LV, return the snapshot lv_segment that uses it */
55struct lv_segment *find_cow(const struct logical_volume *lv)
56{
57	return lv->snapshot;
58}
59
60/* Given a cow LV, return its origin */
61struct logical_volume *origin_from_cow(const struct logical_volume *lv)
62{
63	return lv->snapshot->origin;
64}
65
66void init_snapshot_seg(struct lv_segment *seg, struct logical_volume *origin,
67		       struct logical_volume *cow, uint32_t chunk_size)
68{
69	seg->chunk_size = chunk_size;
70	seg->origin = origin;
71	seg->cow = cow;
72
73	lv_set_hidden(cow);
74
75	cow->snapshot = seg;
76
77	origin->origin_count++;
78
79	/* FIXME Assumes an invisible origin belongs to a sparse device */
80	if (!lv_is_visible(origin))
81		origin->status |= VIRTUAL_ORIGIN;
82
83	seg->lv->status |= (SNAPSHOT | VIRTUAL);
84
85	dm_list_add(&origin->snapshot_segs, &seg->origin_list);
86}
87
88int vg_add_snapshot(struct logical_volume *origin,
89		    struct logical_volume *cow, union lvid *lvid,
90		    uint32_t extent_count, uint32_t chunk_size)
91{
92	struct logical_volume *snap;
93	struct lv_segment *seg;
94
95	/*
96	 * Is the cow device already being used ?
97	 */
98	if (lv_is_cow(cow)) {
99		log_error("'%s' is already in use as a snapshot.", cow->name);
100		return 0;
101	}
102
103	if (cow == origin) {
104		log_error("Snapshot and origin LVs must differ.");
105		return 0;
106	}
107
108	if (!(snap = lv_create_empty("snapshot%d",
109				     lvid, LVM_READ | LVM_WRITE | VISIBLE_LV,
110				     ALLOC_INHERIT, origin->vg)))
111		return_0;
112
113	snap->le_count = extent_count;
114
115	if (!(seg = alloc_snapshot_seg(snap, 0, 0)))
116		return_0;
117
118	init_snapshot_seg(seg, origin, cow, chunk_size);
119
120	return 1;
121}
122
123int vg_remove_snapshot(struct logical_volume *cow)
124{
125	dm_list_del(&cow->snapshot->origin_list);
126	cow->snapshot->origin->origin_count--;
127
128	if (!lv_remove(cow->snapshot->lv)) {
129		log_error("Failed to remove internal snapshot LV %s",
130			  cow->snapshot->lv->name);
131		return 0;
132	}
133
134	cow->snapshot = NULL;
135	lv_set_visible(cow);
136
137	return 1;
138}
139